scholarly journals Salmonella grows massively and aerobically in fecal matter

2019 ◽  
Author(s):  
Teresa Guerrero ◽  
Sonia Zapata ◽  
Gabriel Trueba
Keyword(s):  
Waste Management ◽  
Animal Manure ◽  
Anaerobic Conditions ◽  
Fecal Matter ◽  
Middle Income ◽  
E Coli ◽  
Middle Income Countries ◽  
Intestinal Pathogens ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

SummaryThe use of wastewater for irrigation and animal manure as fertilizer can cause transmission of intestinal pathogens, conditions frequently observed in Low- and Middle-Income Countries (LMICs). Here we tested the ability of Salmonella to grow in the fecal matter; we inoculated freshly isolated Salmonella strains (from chickens) in chicken fecal matter and incubated for 24, 48 and 72 hrs under aerobic and anaerobic conditions. We found that both Salmonella and E. coli multiplied massively in fecal matter outside a host for 72 hrs, being their growth higher in aerobic conditions. Our results have critical implications in waste management, as we demonstrate that aerobic treatments may not be the best to reduce the number of Salmonella in the environment.

scholarly journals Effect of Intracellular Expression of Antimicrobial Peptide LL-37 on Growth of Escherichia coli Strain TOP10 under Aerobic and Anaerobic Conditions

2013 ◽  
Vol 57 (10) ◽  
pp. 4707-4716 ◽  
Author(s):  
Wei Liu ◽  
Shi Lei Dong ◽  
Fei Xu ◽  
Xue Qin Wang ◽  
T. Ryan Withers ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Anaerobic Conditions ◽  
Content Type ◽  
E Coli ◽  
Intracellular Expression ◽  
Aerobic And Anaerobic Growth ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

ABSTRACTAntimicrobial peptides (AMPs) can cause lysis of target bacteria by directly inserting themselves into the lipid bilayer. This killing mechanism confounds the identification of the intracellular targets of AMPs. To circumvent this, we used a shuttle vector containing the inducible expression of a human cathelicidin-related AMP, LL-37, to examine its effect onEscherichia coliTOP10 under aerobic and anaerobic growth conditions. Induction of LL-37 caused growth inhibition and alteration in cell morphology to a filamentous phenotype. Further examination of theE. colicell division protein FtsZ revealed that LL-37 did not interact with FtsZ. Moreover, intracellular expression of LL-37 results in the enhanced production of reactive oxygen species (ROS), causing lethal membrane depolarization under aerobic conditions. Additionally, the membrane permeability was increased after intracellular expression of LL37 under both aerobic and anaerobic conditions. Transcriptomic analysis revealed that intracellular LL-37 mainly affected the expression of genes related to energy production and carbohydrate metabolism. More specifically, genes related to oxidative phosphorylation under both aerobic and anaerobic growth conditions were affected. Collectively, our current study demonstrates that intracellular expression of LL-37 inE. colican inhibit growth under aerobic and anaerobic conditions. While we confirmed that the generation of ROS is a bactericidal mechanism for LL-37 under aerobic growth conditions, we also found that the intracellular accumulation of cationic LL-37 influences the redox and ion status of the cells under both growth conditions. These data suggest that there is a new AMP-mediated bacterial killing mechanism that targets energy metabolism.

scholarly journals Reactivity of nitric oxide with the [4Fe–4S] cluster of dihydroxyacid dehydratase from Escherichia coli

2009 ◽  
Vol 417 (3) ◽  
pp. 783-789 ◽  
Author(s):  
Xuewu Duan ◽  
Juanjuan Yang ◽  
Binbin Ren ◽  
Guoqiang Tan ◽  
Huangen Ding
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Enzyme Activity ◽  
Anaerobic Conditions ◽  
Iron Sulfur Clusters ◽  
E Coli ◽  
Endonuclease Iii ◽  
Iron Sulfur ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Although the NO (nitric oxide)-mediated modification of iron–sulfur proteins has been well-documented in bacteria and mammalian cells, specific reactivity of NO with iron–sulfur proteins still remains elusive. In the present study, we report the first kinetic characterization of the reaction between NO and iron–sulfur clusters in protein using the Escherichia coli IlvD (dihydroxyacid dehydratase) [4Fe–4S] cluster as an example. Combining a sensitive NO electrode with EPR (electron paramagnetic resonance) spectroscopy and an enzyme activity assay, we demonstrate that NO is rapidly consumed by the IlvD [4Fe–4S] cluster with the concomitant formation of the IlvD-bound DNIC (dinitrosyl–iron complex) and inactivation of the enzyme activity under anaerobic conditions. The rate constant for the initial reaction between NO and the IlvD [4Fe–4S] cluster is estimated to be (7.0±2.0)×106 M−2·s−1 at 25 °C, which is approx. 2–3 times faster than that of the NO autoxidation by O2 in aqueous solution. Addition of GSH failed to prevent the NO-mediated modification of the IlvD [4Fe–4S] cluster regardless of the presence of O2 in the medium, further suggesting that NO is more reactive with the IlvD [4Fe–4S] cluster than with GSH or O2. Purified aconitase B [4Fe–4S] cluster from E. coli has an almost identical NO reactivity as the IlvD [4Fe–4S] cluster. However, the reaction between NO and the endonuclease III [4Fe–4S] cluster is relatively slow, apparently because the [4Fe–4S] cluster in endonuclease III is less accessible to solvent than those in IlvD and aconitase B. When E. coli cells containing recombinant IlvD, aconitase B or endonuclease III are exposed to NO using the Silastic tubing NO delivery system under aerobic and anaerobic conditions, the [4Fe–4S] clusters in IlvD and aconitase B, but not in endonuclease III, are efficiently modified forming the protein-bound DNICs, confirming that NO has a higher reactivity with the [4Fe–4S] clusters in IlvD and aconitase B than with O2 or GSH. The results suggest that the iron–sulfur clusters in proteins such as IlvD and aconitase B may constitute the primary targets of the NO cytotoxicity under both aerobic and anaerobic conditions.

Effect of Alternating Aerobic and Anaerobic Conditions on the Economics of the Activated Sludge System

1987 ◽  
Vol 19 (5-6) ◽  
pp. 911-918 ◽  
Author(s):  
S. Y. Ip ◽  
J. S. Bridger ◽  
N. F. Mills
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Sludge Reduction ◽  
Conventional System ◽  
Anaerobic Conditions ◽  
High Quality ◽  
E Coli ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions ◽  
Denitrification Process

Results of our trials demonstrate that the alternating aerobic/anaerobic activated sludge (AAA-CMAS) system is capable of producing effluent of high quality in either fully-loaded or under-loaded conditions. The aeration energy saving and the sludge reduction of the AAA-CMAS system was shown to be of the order of 30% and 15% respectively. Because denitrification process is taking place within the reactor under controlled conditions and not in the sedimentation tank where degree of denitrification cannot be controlled, effluent of the AAA-CMAS system was found to contain much less suspended solids and E. coli counts than that of the conventional system, resulting in further cost saving in chlorination and in back-washing of the filter.

scholarly journals Prevalence of MDR organism (MDRO) carriage in children and their household members in Siem Reap Province, Cambodia

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Shweta R Singh ◽  
Bunsoth Mao ◽  
Konstantin Evdokimov ◽  
Pisey Tan ◽  
Phana Leab ◽  
...  
Keyword(s):  
Final Analysis ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Middle Income ◽  
E Coli ◽  
Middle Income Countries ◽  
Siem Reap ◽  
High Prevalence ◽  
Significant Public Health ◽  
History Of

Abstract Background The rising incidence of infections caused by MDR organisms (MDROs) poses a significant public health threat. However, little has been reported regarding community MDRO carriage in low- and middle-income countries. Methods We conducted a cross-sectional study in Siem Reap, Cambodia comparing hospital-associated households, in which an index child (age: 2–14 years) had been hospitalized for at least 48 h in the preceding 2–4 weeks, with matched community households on the same street, in which no other child had a recent history of hospitalization. Participants were interviewed using a survey questionnaire and tested for carriage of MRSA, ESBL-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) by culture followed by antibiotic susceptibility testing. We used logistic regression analysis to analyse associations between collected variables and MDRO carriage. Results Forty-two pairs of households including 376 participants with 376 nasal swabs and 290 stool specimens were included in final analysis. MRSA was isolated from 26 specimens (6.9%). ESBL-producing Escherichia coli was detected in 269 specimens (92.8%) whereas ESBL-producing Klebsiella pneumoniae was isolated from 128 specimens (44.1%), of which 123 (42.4%) were co-colonized with ESBL-producing E. coli. Six (2.1%) specimens tested positive for CPE (4 E. coli and 2 K. pneumoniae). The prevalence ratios for MRSA, ESBL-producing E. coli and ESBL-producing K. pneumoniae carriage did not differ significantly in hospital-associated households and hospitalized children compared with their counterparts. Conclusions The high prevalence of ESBL-E across both household types suggests that MDRO reservoirs are common in the community. Ongoing genomic analyses will help to understand the epidemiology and course of MDRO spread.

Oxygen concentration affects frequency and range of transconjugants for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1

2020 ◽  
Vol 85 (4) ◽  
pp. 1005-1015
Author(s):  
Kentaro Ochi ◽  
Maho Tokuda ◽  
Kosuke Yanagiya ◽  
Chiho Suzuki-Minakuchi ◽  
Hideaki Nojiri ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Anaerobic Condition ◽  
Environmental Samples ◽  
Aerobic Condition ◽  
Recipient Strain ◽  
Donor Strain ◽  
Anaerobic Conditions ◽  
Filter Mating ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

ABSTRACT The frequency of transconjugants were compared for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1 under aerobic and anaerobic conditions. Filter mating assays were performed with one donor strain and one recipient strain using different donors of Pseudomonas and recipient strains, including Pseudomonas, Pantoea, and Buttiauxella. Under anaerobic condition, frequencies of transconjugants for both plasmids were 101-103-fold lower than those under aerobic condition regardless of whether aerobically or anaerobically grown donors and recipients were used. To compare the transconjugant ranges under aerobic and anaerobic conditions, conjugation was performed between the donor of pBP136 and recipient bacteria extracted from environmental samples. Several transconjugants were uniquely obtained from each aerobic or anaerobic condition. Our findings indicate that a plasmid can differently spread among bacteria depending on the oxygen concentrations of the environment.

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